Variable Air Volume(VAV) with Reheat

Variable Air Volume, VAV w/ Reheat operates very similarly to the 75F DAB profile and in fact uses the DAB zone profile. The VAV w/ Reheat system profile is designed for buildings where there is a central RTU and up to 48 terminal VAV boxes with reheat. The central RTU is primed to provide cool air whenever a single zone needs it and the terminal units will reheat the air if the zone is below desired set point.

The VAV w/ Reheat system profile works with the DAB zone profiles to achieve the optimal comfort in each zone. The VAV w/ Reheat profile is setup to control an RTU with staged compressors, furnace, with staged fan or a VFD. If you have a true VAV with modulating equipment, there are options. One of which is our Modulating RTU Control system profile. If you are looking for other options, please contact us for more information.

The thought for this profile is that if any one zone needs cooling and all zones are configured with reheat, that the RTU will be in cooling mode. If and when all zones need heating, the RTU will fire to heat the spaces. This is similar to the concept of morning warm up, but this can happen at any time of day if the zones are all dropping below setpoint.

Image 3- Very simple, all zones need cooling. The RTU starts cooling.

Image 4 - All zones need heating. In this case the RTU furnace and reheats engage. The zone dampers open.

Image 5 - A single zone needs cooling and two zones need heating. The RTU engages cooling and the zone that needs it opens its damper all the way to cool the zone. The two that need heating restrict the airflow with the dampers and engage the reheat.